At the age of fifteen, McCartney met Lennon and his band, the Quarrymen, at the St Peter's Church Hall fête in Woolton on 6 July 1957. The Quarrymen played a mix of rock and roll and skiffle, a type of popular music with jazz, blues and folk influences. The band invited McCartney to join soon afterwards as a rhythm guitarist, and he formed a close working relationship with Lennon. Harrison joined in 1958 as lead guitarist, followed by Lennon's art school friend Stuart Sutcliffe on bass, in 1960. By May 1960 the band had tried several names, including "Beatals", "Johnny and the Moondogs" and "the Silver Beetles". They adopted the name "the Beatles" in August 1960 and recruited drummer Pete Best shortly before a five-engagement residency in Hamburg.

Casser lived in Liverpool in the late 1950s, having previously worked in the Merchant Navy. As singer and rhythm guitarist, he formed a trio, Cass & the Cassanovas, in May 1959, with singer and guitarist Adrian Barber (born 13 November 1938, Ilkley, Yorkshire), and drummer and singer Brian J. Hudson (born Brian James Hudson, 21 April 1938, Cleveland, Yorkshire). After a few months, Hudson left and was replaced by Johnny Hutchinson (born 18 July 1940, Malta), known as Johnny Hutch. In need of a bass guitarist, Hutchinson then brought in Johnny Gustafson (born 8 August 1942, Liverpool) in December 1959. At that time Gustafson did not have a proper bass guitar so Barber converted an acoustic for him. The group became popular playing a wide range of music, from Latin American music to rock and roll, in dance halls in the Liverpool area. Casser also started his own music club in Liverpool, the Casanova Club, whose guest groups included one known at the time as the "Silver Beetles"; according to some reports, Casser had suggested that they change their name from the earlier spelling of "Beatals" which Casser found "ridiculous". In May 1960 Cass & the Cassanovas took part in auditions in front of leading manager Larry Parnes who was looking for backing bands for his stable of pop singers. The group secured a place as backing group for singer Duffy Power and toured with him. By this time, Casser had begun using the stage names of "Casey Jones" and "Casey Valence".

In March 1957, John Lennon, then aged sixteen, formed a skiffle group with several friends from Quarry Bank school. They briefly called themselves the Blackjacks, before changing their name to the Quarrymen after discovering that a respected local group was already using the other name. Fifteen-year-old Paul McCartney joined as a rhythm guitarist shortly after he and Lennon met that July. In February 1958, McCartney invited his friend George Harrison to watch the band. The fourteen-year-old auditioned for Lennon, impressing him with his playing, but Lennon initially thought Harrison was too young to join them. After a month of Harrison's persistence, they enlisted him as their lead guitarist. By January 1959, Lennon's Quarry Bank friends had left the group, and he began studies at the Liverpool College of Art. The three guitarists, billing themselves at least three times as Johnny and the Moondogs, were playing rock and roll whenever they could find a drummer. Lennon's art school friend Stuart Sutcliffe, who had recently sold one of his paintings and was persuaded to purchase a bass guitar, joined in January 1960, and it was he who suggested changing the band's name to Beatals, as a tribute to Buddy Holly and the Crickets. They used the name until May, when they became the Silver Beetles, before undertaking a brief tour of Scotland as the backing group for pop singer and fellow Liverpudlian Johnny Gentle. By early July, they had changed their name to the Silver Beatles and by the middle of August to the Beatles.